MRO Today - Data loggers on the government payroll

Data loggers on the government payroll

New York state government offices need a steady, reliable supply of electricity, even during emergencies. When the State Office of General Services made the decision to replace emergency backup generators for their offices in Albany, the first challenge engineers faced was to accurately assess the power needs of the more than 20 buildings in the complex.

Whenever the buildings were cut from the main power grid for any reason, emergency generators would have to supply enough power for lighting and other essential services. Ryan Thordson, an energy engineer working with the Office of General Services and the New York Power Authority, the state-owned power supplier, had the task of assessing the emergency energy load so that the 5-megawatt, multi-million-dollar generators could be sized correctly.

One way to assess energy loads is to rely on the power utility to measure an entire building’s energy usage, but for this project, the engineers need finer detail. The challenge here was to measure power requirements at the individual circuit level, which meant collecting data from over 200 points spread over 20 buildings, all within the project’s six-month timeline.

Data loggers like these enabled a cost-effective and highly accurate circuit-level energy assessment of New York State’s goverment building complex in Albany.

Thordson’s experience with energy assessment and logging devices led him to recommend small, battery-powered portable data loggers for the project. The State Office of General Services purchased 16 HOBO Energy Logger Pro data loggers from Onset Computer Corporation (www.onsetcomp.com) and connected each with a pulse input adapter cable to a WattNode kWh transducer. The transducer monitors current and voltage and converts them to a pulse proportional to kilowatt-hours that is then sent to the HOBO Energy Logger Pro, which logs the resultant data.

The data loggers took readings once every minute, 24 hours per day. Once a week, Thordson downloaded the data from each circuit into his laptop. When he connected the loggers to his computer via a USB cable, Onset’s HOBOware Pro graphing and analysis software recognized the logger and downloaded the week’s data in seconds. He then connected the loggers to new nearby circuits or moved them to another building.

Thordson estimates that by buying the loggers and doing the collection and analysis themselves, the New York State Office of General Services has been able to do the study for about $25,000, a significant savings when compared to the $200,000-$250,000 an engineering firm would charge for essentially the same thing. And, when the units finish collecting energy-use data, he expects he’ll be right on target with providing energy profiles to the engineers responsible for sizing the generators. Item 127

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